San Diego State University
Department of Civil, Construction, and Environmental Engineering
ENVE 441 – Water Treatment Engineering
Due on Friday, December 7, 2018 at 1:00 p.m.
A new community near Rancho San Diego in San Diego County requires a water
treatment plant (WTP) that meets current regulations. You have been assigned to design the
basic water treatment processes for a 4 mgd conventional WTP with ozone (rapid mix,
coagulation, sedimentation, rapid sand filter, and ozone/chlorine disinfection). The peak flow
to average flow ratio is 1.5:1 for purposes of determining the number of treatment trains. The
WTP uses Sweetwater Reservoir as its source water with characteristics listed on the next page.
Design temperature range 5oC to 30oC. The geology limits basin depth to 20 feet.
For this project, you will prepare a report on the design of the WTP processes. Include
any necessary design criteria, chemicals, and calculations to design and size the processes. This
is an independent research project; you are expected to review available reference information
and determine the appropriate formula for sizing the processes on an individual basis.
The report should conform to the following requirements:
1. The report must be written using Microsoft office or other word processing software.
2. The report should include one cover page, at least two pages of text (12 point font,
single spaced), a process schematic with chemical addition indicated, a plan view
showing treatment trains, meq/L table, meq/L liter bar chart, water quality table
(influent vs. MCL), a summary table with design criteria and process dimensions for
each process, chemical equations, at least one photo, at least one calculation page,
and one reference page. Minimum is 6 total pages.
3. Submit hardcopy and electronic copy (by email – firstname.lastname@example.org) of the report
by the due date and time.
Introduction – Discuss the WTP type and capacity, determine the number of treatment trains, draw the process schematic with chemical addition locations indicated, draw a simple plan view with treatment trains. (text, schematic, plan view) (can be hand drawn)
Water Quality – prepare the influent water quality table to calculate milliequivalent per liter, draw the milliequivalent per liter bar chart, calculate hardness; list regulatory requirements MCL versus actual influent water quality in a table and indicate whether each constituent complies (water quality table, meq/L bar chart, MCL table vs. influent)
Process Descriptions – Briefly discuss the function of each process. What does it involve? How does it work? List Chemical Equations for chemicals added (text, chemical equations, photo)
Design Criteria – List the criteria used to design and size each process (summary table)
Size Process – Size each process (summary table/calculations)
References – List your references (reference page)
Process Sizing Requirements: Rapid Mix – Volume, Length, Width, Depth, G, mixer hp, chemicals required(use L=W=D) Flocculation – Volume, Length, Width, Depth, Detention Time, Velocity, G, mixer hp Sedimentation – Volume, Length, Width, Depth, Detention Time, Velocity, Overflow
Rate, Weir Length, Number of Weirs, Traveling Bridge or Chain-and-Flight Rapid Sand Filter – Filtration Rate, Media Diameter, Bed Depth, Required Head, Length,
Width, Depth, Quantity of Backwash Water, Percentage Used for Backwash Water Disinfection – Disinfection Contact Basin used for both Chlorine or Ozone with Residual
Chlorine. Determine Concentration, Contact Time, Length, Width, Depth (for governing criteria of chlorine or ozone)
The project will be evaluated on the basis of technical quality, accuracy of information, and readability. The project will be graded out of 100% and the breakdown is as follows:
1. Plant layout, introduction, readability, organization of the report, references – 25% 2. Process descriptions, chemistry, technical quality, accuracy of information – 25% 3. Design criteria, sizing, calculations – 50%
Conventional Water Treatment Plant with Ozone
Influent Water Characteristics (2017)* (from Sweetwater Reservoir), average values
Turbity 7.9 NTU
Color 43 units
Total Organic Carbon 11.5 ppm
Calcium 100 ppm
Magnesium 25.6 ppm
Sodium 160 ppm
Bicarbonate 200 ppm
Sulfate 177 ppm
Chloride 245 ppm
Iron 152 ppb
Manganese 203 ppb
*For other parameters see “Sweetwater Reservoir” in handout from Lecture
OZONE and Cl2